Abrading machine



Sept. 15, 1942. is. w. STACEY ABRAD'ING MACHINE Filed Aug. 1, 1940 4 Sheets-Sheet l Sept. 15, 1942. E w. STACEY 2,295,695

ABRADING MACHINE Filed Aug. 1, 1940 4 Sheets-Sheet 2 Fig.2.

Sept. 15, 1942. E. w. S TACEY ABRADING MACHINE Filed Aug. 1, 1940 4 Sheets-Sheet 3 mg v Sept. 15, 1942. E. w. STACEY 2,295,695

ABRADING MACHQINE Filed Aug. 1, 1940 4 Sheets-Sheet 4 24 III /06 m5 Patented Sept. 15, 1942 UNITED STATES PATENT OFFICE 2,295,695 ABRADING MACHINE Ernest W. Stacey, Beverly, Mass, assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application August 1, 1940, Serial No. 349,161

7 Claims.

This invention relates to abrading machines and is herein illustrated and described as embodied in a buffing machine of the type disclosed in United States Letters Patent No. 2,218,537, granted October 22, 1940, upon the application of Norwood H. Knowlton. Such machines are conveniently used for operation upon shoe parts, such as outsoles which are to be buffed on their grain surfaces prior to their attachment to shoes. Machines of the type under consideration include in their organization a buffing tool, means for feeding a work-piece past the buffing tool, and a device for holding the work-piece in engagement with the bufiing tool during its progress past the tool.

It is an objectpf the present invention to provide a buffing machine having improved means for holding a workpiece in engagement with a bufiing tool. In the illustrated machine the work is held against the bufling tool by a pressing means which comprises a plurality of plungers arranged in staggered rows lengthwise of a buffing roll and actuated by pneumatic pressure. Each of these plungers is slidably mounted in a wall of a fluid pressure chamber, the outer end portion of the plunger having the shape of a relatively narrow, blunt edged blade for slidably engaging the moving work-piece. Such a pressing device is of particular convenience in a machine of the type disclosed herein, wherein the axis of the buffing roll is in skewed relation to the direction of feed of the work to provide an axial component of relative movement between the abrasive surface of the buffing roll and the work-piece. The effect of such axial component is to minimize any tendency of the grit of the bufiing roll to cause visible scratch marks upon the surface of the work.

Other objects of the invention are to provide an improved arrangement for feeding a workpiece past the buffing roll, and an improved mechanism for blowing jets of air against the bufiing roll to remove dust resulting from the operation of the roll upon the work.

These and other objects and features of the invention will appear more fully from the following detailed description when read in connection with the accompanying drawings and will be pointed out in the appended claims.

Referring now to the accompanying drawings:

Fig. 1 is an end elevation of the machine;

Fig. 2 is a plan view of the machine with the dust hood removed;

Fig. 3 is a sectional view in end elevation taken on the line IIIIII-of Fig. 6;

Fig. 4 is a detail showing one of the workpressing fingers;

Fig. 5 is a view of the outer portion of the finger shown in Fig. 4 looking in the direction of the arrow;

Fig. 6 is a plan view of the work-supporting and feeding arrangements with the dust hood and bufling roll removed; and

Fig. '1 is a fragmentary showing in front elevation of the parts shown in Fig. 6.

The machine in its general organization comprises a buffing roll 10 (Figs. 2 and 3) against which work-pieces such as a pair of soles A and A are yieldably held by a plurality of presser fingers [2. The bufiing roll I0 is long enough to enable the soles A and A to be presented simultaneously in side-by-side relation, the sole A being fed by a plurality of right hand feed rolls l4, l6, I8, 20 and 22, and the sole A being fed by a corresponding plurality of left hand feed rolls l4, l6, I8, 20 and 22' (Fig. 6). The feed rolls are arranged in pairs l4 and I4, l6 and [6, etc. with the two rolls of each pair in endto-end relation, that is, approximately coaxial with each other, but mounted independently of each other to enable each roll to yield in accordance with the thickness of the particular sole which it engages. These rolls are all deeply knurled to insure a good frictional grip upon the work. The work is introduced by the operator upon a substantially horizontal work table 24 having a smooth upper surface leading to the first feed roll I4 and provided with guide strips 25. The leading end of the sole A, upon being engaged by the feed roll I4 is advanced to the second feed roll Hi, the two rolls l4 and I6 meanwhile pressing the work-piece upwardly against a smooth under surface formed on a feed plate 26. The leading end of the sole A thereupon enters between the presser fingers l2 and the buffing roll I0, and thence passes over the feed rolls l8 and 20 which press it against the smooth under surface of a feed plate 28. As shown in Fig. 3, the feed plate 28 is inclined upwardly to curve the work-pieces about the buffing roll and thereby prolong their engagement with the abrasive. The sole A thereupon passes a rotary brush 30 which cleans dust from the upper surface of the sole, the brush extending downwardly through a slot in the feed plate 28. After passing the brush 30, the sole A is engaged between the feed roll 22 and the feed plate 28. Except for the fact that the sole A is engaged by a different set of feed rolls, its passage through the machine is similar to that of the sole A. A

of resilient material 42 and an abrasive cover 44 of sand paper or other abrasive sheet material. The roll I is mounted upon a shaft 46, which is journaled in bearin'gs dB and 59 carried by the end walls 35 and'tfi respectively. As shown in Fig. 2, the axis of the shaft is not parallel to the transverse center line of the machine, but is somewhat oblique, while the path of feed of the work-pieces, as later will be pointed out, is parallel to the longitudinal center line of the machine. It is thus. evident that the axis of the buffing roll is ins'kewed relation to the direction of feed of the work-pieces. The rotation of the roll, by reason of. this skewed relation, will cause an endwise or axial component of movement to be developedbetween the abrading surface of the roll andthe workpiece. An advantage of this endw ise component resides in the fact thatany more prominent particles of grit upon the sand-paper 44 which mightcausevisible scratch marks upon the Work if-allowed to retrace their former paths upon the Work will; upon succeeding engagement, be laterally displaced from such paths and therefore willnot gouge more deeply into the Work and extend linesalready formed. The visibility of such .marks when thus distributed is negligible; V

Eachof the presser fingers l2 consists of a cylindrical shank 52 (Figs. 4 and 5)- terminat ing at its upper'end in a thin blade-likejhead 54. -The head 54 is. relatively long and narrow, its length being considerably greater than the diameter oftheshank 52 and its width being considerably less. The .head .54 is transversely rounded to provide a blunt edge 56 and is also longitudinally rounded to facilitate the entryof work-pieces between it and .the 'bufiing roll and to minimize friction against the work-pieces. Each otthe shanks52 operates as a plunger and is-individually guided in a pair of coaxial bores 58and 50 formed in a hollow box-like member 62,-which extends substantially the length of the bufilng roll in and which formsthe upper closure wall of an air pressure receptacle or chamberfill', the box 62 being secured to the receptacle 54 by screws 6|. 'The bores 58 and 50. are arrangedin three parallelrows, each set of bores being "staggered with respect to the neighboring boresof the other rows toenable the .fingers to operate over an .arc of contact about the axis of thebuffing roll and also toprovide for, a close spacing. .of ..the heads 54. Secured to the bottom 'of lthe'receptaclefid are a pair of angle irons (Figs. .3 and-7) having spaced depending flanges E5 whichembrace a block. 66. Each end of the blookiifi has a lug 61 which is secured to the uppersurface ofa supporting plate 68. Each of the. plates 68 is secured to the base-plate 34 by screws 69, therear screws 69 passingthrough wedge-blocks E0 to incline the plate 68 upwardly. Theplates 68 are thus .secured in such a position as to bring. the three rows of bores all parallel to the. axis of the bufiing roll I!) and with the radial with respect to the bufiing roll. The fingers l2 engage the work-pieces slightly beyond the vertical center line of the buffing roll in view of the fact that the work-pieces are curved upwardly around the buffing roll to prolong their engagement therewith. The shanks 52 accordingly tilt backwardly, and the purpose of the inclination of the plates 68 is to provide this tilt. The flanges 65 are secured to the block 66 by clamping bolts H which extend through heightwise slots '53 formed in the block to accommo- .date adjustment of the receptacle 64 toward and from the bufiing roll. Such adjustment is determined by screws (Fig. 7) threaded into the lugs El and having knurled heads l5. These screws also have rounded upper end portions above the heads 15 for engagement with the under surface of the receptacle 64.

Airiunder pressure is supplied to the receptaclet i through a conduit 12 from any convenient source. The air pressure may be controlled .by a reducing valve (not shown) of any well-known type. The fingers l 2 are held against expulsion by the air pressure by means of screws 14 threaded axially into the inner ends of the shanks 52 and having heads of greater diameter than the bores Gil. The fingers thus normally occupy their outermost positions, as shown in Figs. 3 and 4, but may yield inwardly to accommodate the thickness of a work-piece passing between them and the buffing roll. The normal positions of the fingers toward or from the buffing roll is determined by the adjustment of the screws 15. This adjustment shouldprovide just suflicient clearance to prevent contact between the'fingers and the buffing roll, and it does not have to be varied for work-pieces of greater or less thickness because the pressure exerted by the air is independent of the thickness of the work. It is evident that each finger may yield independently of the others to accommodate local variations of thickness, such as may occur in a skived work-piece. The blade-like heads 54 are arranged parallel to each other, their thickness being sufficient to keep each head substantially in sliding engagement with its neighher. The heads of the end fingers are maintained substantially parallel to the longitudinal center line of the machine, which is also in the direction of feed, by smooth surfaces formed on upward extensions 16 of the box 62. The engagement of each head with its neighbor maintains all of the intermediate heads in similar center row in a' plane which is substantially alinement.

A supplemental presser 78 (Fig. 3) in the form of a resilient metal plate secured to the top of the box 62 holds the Work against the bufiing roll at a locality between the fingers l2 and the first of the rear feed rolls l8 and I 3.

The feed rolls l4 and I6 are carried upon short shafts 8i and 82 (Fig. 6)' respectively, which are both journaled in a block84. The block St is cut away to provide'three bearings 83, 88 and 9G for the shaft 86, these bearings being separated by spaces 92 and 94. A block 96 has two portions 98 and H?!) which extend into the spaces 92 and 94 respectively and which also constitute bearings for the shaft at said spaces. The two blocks 8d and 96 thus constitute a hinge, of which the shaft 88 is the pintle. The block 96 has two spaced extensions I02 and H04 which are mounted for free pivotal swinging movement upon a transverse shaft E06 extending the full width of the machine and journaled in bearings carried by the end walls 33 and 38. The

block 96 is held against endwise movement, or lateral movement with respect to the machine,

by engagement with the end wall 38 at one end and with a collar I08 secured upon the shaft I06 at the other end. The block 84 is urged upwardly toward the feed plate 26 by a plunger IIO (see also Fig. 3) which engages the under surface of the block and which is slidably mounted upon a post H2 secured in the base-plate 34. The upper end of the plunger H is rounded to facilitate rocking'of the block 84. Surrounding the lower portion of the post H2 and interposed between the base 34 and a flange on the plunger I I0 is a coil compression spring I I4, which urges the plunger and thereby the block 84 upwardly to a stop position adjustably determined by a pair of stop screws II6 threaded through the feed plate 26.

The feed rolls I8 and 20 ar mounted upon short shafts H8 and I20 respectively, these shafts being journaled in a block I22, which, in turn, is hinged to a block I 24. Th shaft I20 serves as the pintle of the hinge, the arrangement being similar to that of the blocks 84 and 98. The block I24 is pivotally mounted upon a shaft I26, which extends transversely the full width of the machine and is journaled in bearings mounted in the respective end walls 36 and 38. The block I 22 is urged upwardly toward the feed plate 28 by a plunger I28 slidably mounted upon a post I30 and urged upwardly by a compression spring I32. The plunger I28 has a rounded upper end upon which the block I22 can rock or tilt. Upward movement of the block I22 is adjustably limited by a pair of stop screws I34 threaded through the feed plate 28.

The feed roll 22 is mounted upon a short shaft [36, which is journaled in a block I38 pivotally mounted for free swinging movement upon the shaft I26. The block I38 is urged upwardly toward the feed plate 28 by a plunger I40 slidably mounted upon a post I42 and urged upwardly by a coil compression spring I44 to a stop position adjustably determined by a stop screw I46 threaded through the feed plate 28 and engageable with the upper surface of the block. The posts I30 and I42 are secured in a stationary bracket I48 which is bolted to the base-plate 34, the posts being inclined from the vertical at such an angle as to bring them into perpendicular relation to the feed plate 28.

The provisions for mounting the left hand feed rolls I4, [6, I8, 20' and 22' are similar to the provisions for mounting the right hand feed rolls I4, I6, I8, 20 and 22 except for a right to left reversal to bring the left hand members into symmetrical relation to the right hand members. Further description of these left hand members may therefore be omitted, and wherever the left hand members are referred to individually or shown in the drawings, they will be identified by the same reference numerals as their right hand counterparts, the left hand members however being distinguished from the right hand members by the use of primed numerals.

The shafts I06 and I26 and all the feed rolls are parallel to the transverse center line of the machine. The feed of the work-pieces therefore takes place in the direction of the longitudinal center line of the machine, while the direction of movement of the abrading surface of the roll I0 is oblique to the direction of feed of the workpieces for a purpose which has already been mentioned.

The brush 30 is mounted upon a shaft I50 journaled in bearings formed in lugs I5I extending from the respective ends of a transvers bracket I52 which is pivotally supported for free swinging movement by two coaxial pivot pins I54 secured in the respective end walls 36 and 38. The bracket I52 is urged downwardly by a coil compression spring I56 interposed between the bracket and a flange I58 extending from the adjacent end wall 38. The spring I56 surrounds a post I60 secured in the bracket I52 and extending loosely through an opening in the flang I58. A nut I62 threaded upon the upper portion of the post I60 adjustably limits the downward movement of the bracket I52 under the influence of the spring I56.

For disposing of the dust which arises from the operation of the bufiing roll upon the work, the upper portion of the machine is housed in a dust hood having a stationary portion I64 extending between and supported by the respective end walls 36 and 38. A forward extension I66 of the hood is pivotally mounted upon the stationary portion by a hinge I68 to enable it to be raised for the purpose of providing access to the bufling roll. The hood I64 communicates with a suction outlet I10 adapted for connection to an exhaust fan or to the usual suction system pro- Vided in factories where bufl'ing operations are performed. An opening I12 between the rear portion of the hood I64 and the receptacle 32 is left to provide for the exit of finished workpieces. A baffie I13 supported upon th bracket I52 directs the dust laden air to the outlet I10. A curved guard I15 of sheet metal shields the brush 30 from dust thrown off the buffing roll.

Supported by the hinged portion I66 of the dust hood and extending parallel to the buffing roll I0 is a pipe I14 having a longitudinal slit I16 directed toward the periphery of the bufling roll at such an inclination as to cause jets of air issuing therefrom to oppose the peripheral air current set up by the rotation of the roll. The pipe I 14 is connected by a flexible conduit I18 (Fig. l) to a valve chamber I 80, which is supplied by a pipe I82 with air under pressure from any suitable source of supply. A valve in the chamber I is operated through a lever I 84 to provide for intermittent blasts of air. To this end the lever I84 i connected through a link I86 to a rocker arm I88 fulcrumed upon a stationary pin I89 and having an extension I90. The valve is normally held closed by a tension spring I92 anchored at one end to the end plate 36 and connected at its other end to the lever I84. The valve is opened periodically by a pin I94 which is brought into engagement with the extension I by mechanism later to be described.

The driving arrangements will now be described. Secured upon the bufllng r011 shaft 46 is a pulley I96 (Fig. 2) which is driven through a belt I98 from any convenient source of power. Secured upon the brush shaft I50 is a pulley 200 driven by a belt 202, which, in turn, is driven from a pulley 204 (Fig. 1) secured upon a stub shaft 206. A bracket 208, which is pivotally mounted for adjustment upon a stationary bracket 2I0 secured to the end wall 38, carries a bearing in which the shaft 206 is journaled. Secured to the pulley 204 and rotatable therewith is a pulley 2I2, which is engaged by the belt I98 to transmit drive through the belt 202 to the brush 30.

For driving the feed rolls, there is provided a pulley 2I4 (Fig. 1) secured upon a transverse shaft 2I6 journaled in bearings mounted in the irameqdil. The pulley 2I4is driven through a bel m from any convenient source :cf power. Se-

cured upon the shaft2l5 is a .pinion 220', which engages ,a gear .222 carried by-astubshaft 224 mounted in theend wall :38. Thei'gcar 2.2.2 drives a gear 226* secured upon a stubrshaft 228 carried by the right handend wall 38. Mounted upon the shaft 228 in fixed relation to the gear 226 is a pinion 230 which drives a gear 232 (Fig. 2) keyed upon the right hand end of'the shaft'l66.

It will be'convenient, because of the fact that the gearing is best shown in Fig. 1, to consider first the drive of the feed rolls adjacent to the left hand end wall 36, that is, the feed rolls indicated by primed reference numerals. The gears associated with these feed rolls will be indicated also by primed reference numerals, While the gears associated with the right hand feed rolls, being directly in back of and therefore obscured by the left'hand feed roll gearing from the viewpoint of Fig. 1, will, when shown in other figures, be indicated by" corresponding unprimed numerals. i

Keyed upon the 'left'hand end of theishaft I66 (Figs. 1 and 2) is a gear 232 in driving engagement with a gear 234 keyed upon the shaft 80. A pinion 236 coaxial with and fixed to the gear 234 drives an idler gear 238 mounted on a stub shaft 246 which is mounted in a lug 242 (Fig. 7). This lug 242 is the left hand counterpart of a lug 242 (Fig. 3) extending downwardly from the block 84. The idler gear 238' drives a gear 243 mounted on the shaft 82. The shafts .8 82 and 246' pass through holes in the end wall 36 large enough to provide ampleclearance for the movements of the shafts in yielding to accommodate the thickness of a work-piece. 'The hole for the shaft'24 is indicated by the reference numeral 24I in Fig. 7; its right hand counterpart 24I is shown in Fig. 3. It is evident that the gears 2362238 and 243 will always be in mesh with each other notwithstanding these movements, for the reason that their respective shafts are all mounted in parallel relation in the same block 64'. Furthermore, the gear 234 is always held in mesh with the gear 232 bythe block 96 operating as a link. The train of gears from the shaft I66 to the shaft 82' will, therefore, always be in mesh notwithstanding the floating :movements of the feed rolls. 7

For driving the feed rolls I8, and 22 there is provided a gear 244 (Figs. 1 and 2) carried by a stub shaft (not shown) mounted in the right hand end wall 38 and driven by the gear 222.

Coaxial with the gear 244 and in fixed relation thereto is a pinion (not shown) which drives a gear 256 (Fig. 6) secured upon the shaft I26. Secured upon the left hand end of the shaft I26 is a gear 256 which drives a gear 252' secured upon the end of the left hand feed roll shaft I36. The block I38 operates as a link to hold the gear. 252 in mesh. The gear 250 also drives a gear 254 secured upon the end of the left hand feed roll shaft I20. The block I24 operates as a link to hold the gear 264 in mesh. Also keyed upon the shaft I20 is a pinion 256 which drives an idler gear 258 mounted on a stub shaft 266' carried by a lug (not shown; see Fig. 3 for right hand counterpart 262) extending from the block I22. The idler gear 253 drives a gear 264 secured upon the end of the feed wheel shaft 8'. It. isevident that, by reason of the above-described arrangement of gears, drive may be trans- 'mittedto. the feed rolls;I3 20 and 22 regard- "less of the floating movements of the feed rolls.

The shafts I36, I20, II 8 and 260 pass through holesin the adjacent end wall large enough to provide ample clearance for the floating move ments of these shafts. The hole for the right hand counterpart of the shaft 260' is indicated by-the reference numeral 26I in Fig. 3.

Although the gears for driving the right hand feed rolls are invisible in Fig. 1, such gears are directly in back of their left hand counterparts as shown in that figure. The preceding descriptiontherefore serves also to indicate the arrangement of the right hand feed roll gears; when thusread however'the primes should be dropped fronrthe reference numerals to avoid confusion.

It has already been pointed out that the shaft I66 serves not only as a pivot for the blocks 96 and '96 but it operates also to transmit drive from the gear 232 to the gear 232.. If desired a pair of coaxial shafts, with ample clearance between them, may be employed in place of the singleshaft I66 to perform these separate functions, the outer shaft of such pair being stationary to serve as the pivot and the inner shaft being rotary to transmit drive. A similar substitution may be made for the shaft I26.

For operating the valve I86, there is provided an idler gear 266 (prime numbers need no longer be employed for the members now to be described because these members, even though some of them may obscure similar members at the opposite end of the machine, have "no functional counterparts) driven by the gear 256 and carried by a stub shaft 268 mounted in the end wall 36. A pinion 21G coaxial with and secured to the gear 266 drives a gear 212 carried by a stub shaft 214 mounted in the end wall '36. A pinion 216 coaxial with and secured to the gear 212 drives a gear 218 carried by a stub shaft 28!] mounted in the end wall 36. The pin'l94 which'operates the valve I extends from the face of the gear 218 which is driven at relatively slow speed by the train of gearing already described.

The operation of the machine will be readily understood in view of the foregoing description. The soles A and A are introduced upon the work table 24 by hand. The first set of feed rolls thereupon grip the work-pieces frictionally and press them against the feed plates to cause the work-pieces to advance into operative engagement with the bufiing roll. During such engagement the plungers I2 hold the work-pieces against the buffing roll with substantially uniform pressure notwithstanding local variations of thickness in the work-pieces. The blade-like heads 54 of the plungers extend in the direction of feed and help to hold the work against any tendency to move laterally as a result of the skewed relation of the bufiing roll. While a work-piece is engaged by both feed rolls of the first set, that is, the rolls I4 and I6, or I4 and I6, it is firmly held by these rolls against lateral diversion by the buffing roll. 'By the time the trailing end of the work-piece has passed the roll I4 and I4, the leading end will have come into engagement with the roll I8 or I3; and by the time the trailing end has passed the roll I6 or I6, the leading end will have come into engagement with the roll 26 or 26. It is clear therefore that the work-piece during its entire passage past the bufiing roll is under the control of at least two feed rolls, and such control maintains the direction of feed parallel to the longitudinal center line of the machine. After passing the bufling roll the work is fed past the brush and is then deliverd into the receptacle'32.

It will be noted that the positively driven feed rolls not only carry the work to and past the buffing roll but also hold the work against any tendency of the buffing roll, which rotates in a counterclockwise direction as seen in Fig. 3, to speed up the feed. By reason of the arrangements for mounting the feed rolls, each feed roll of the right or left hand group yields independently of the other rolls of that group, and also of its counterpart in the other group.

Having thus 'described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An abrading machine comprising an abrading roll, means for feeding a work-piece past said abrading roll, the axis of the roll being in skewed relation to the direction in which the work-piece is fed by the feeding means to provide an axial component of relative movement between the abrasive surface of the roll and the work-piece, a plurality of rows of individually yieldable presser fingers extending parallel to the axis of the roll, the fingers of one row being staggered with relation to the fingers of another row, and pneumatic means acting upon said fingers to cause the fingers to press the Work-piece against the roll.

2. A device for pressing a work-piece against a tool comprising a receptacle for holding a pressure fluid, and a plurality of plungers, said receptacle having a wall provided with a plurality of rows of openings in which said plungers are mounted in staggered relation with the inner ends of the plungers subject to the pressure within the receptacle, the outer ends of the plungers being in the form of relatively narrow bluntedged blades each overlapping its staggered neighboring blades, the purpose of said blades being to press the moving work-piece against the abrading tool.

3. In a machine of the class described, a pair of rolls adapted for frictional engagement with a work-piece, a shaft for each of said rolls, a support in which said shafts are mounted in parallel relation, a member pivotally connected to one of said shafts, and a pivotal mounting which enables said member to be swung about an axis parallel to said shafts, said support being pivotable about the roll shaft to which said member is pivotally connected, whereby each of said rolls may move bodily independently of the other while engaging a work-piece without disturbing their parallel relation to each other and to said axis.

4. In a machine of the class described, a pair of feed rolls, shafts for said feed rolls, a support in which said shafts are journaled in parallel relation, a gear on each of said shafts, an idler gear in mesh with each of said gears and carried by said support, a third shaft, a link having a bearing on one of said feed roll shafts and having another bearing on said third shaft, said link being free to swing about said third shaft to accommodate tilting movement of said feed roll support while maintaining said feed rolls parallel to each other and to said third roll, a gear on said third shaft for driving the gear on the feed roll shaft on which said link has a bearing, and means for driving said driving gear.

5. In a machine of the class described, a pair of feed rolls, a shaft for each of said rolls, a block in which the shafts are journaled in parallel relation, a third shaft parallel to said feed roll shafts, a link having a bearing on said third shaft and also on one of said feed roll shafts to maintain the feed roll shafts in said parallel relation to said third shaft while leaving said block free to rotate about the third shaft and to tilt about said one feed roll shaft, a springpressed plunger acting against said block to cause the feed rolls to press against one surface of a work-piece, and means engageable with the opposite surface of the work-piece to hold the workpiece against the pressure exerted by said plunger.

6. An abrading machine comprising an abrading tool, means for effecting relative movement between said tool and a work-piece, a nozzle for directing a jet of air against said abrading tool to blow dust therefrom, a connection from said nozzle to a source of air under pressure, and control means operated by said movement-effecting means for alternately stopping and releasing the flow of air from said nozzle, thereby causing the air to be delivered from said nozzle periodically.

7. An abrading machine comprising a rotary abrading tool, means for driving said tool, a nozzle for directing a jet of air against said tool to blow dust therefrom, a connection from said nozzle to a source of air under pressure, a valve in said connection for controlling the flow of air from said nozzle, and means operated by said driving means for opening and closing said valve periodically.

ERNEST W. STACEY. 

